On Thursday 20th May the SNCV were out at Beddington Farmlands doing some Himalayan Balsam removal. Himalayan Balsam (Impatiens glandulifera) is a non-native species, which was first introduced into Britain in the mid-19th century as an ornamental plant. You may be familiar with this well-known invasive plant, as it has become fairly widespread and common across much of the UK. You will usually find it along river banks or other areas of damp ground, where it thrives.
Himalayan Balsam © Crown Copyright 2009
Since it was introduced into Britain, Himalayan Balsam has managed to escape from gardens and rapidly establish along waterways. As the name suggests, Himalayan Balsam originates from the western Himalayas but has flourished in the slightly warmer British climate. They are prolific growers, and are actually the tallest annual plant in Britain (they can grow up to 10 foot high!).
It is not hard to see why Victorian gardeners were originally drawn to these plants, as they produce an array of attractive pinkish-purple flowers at the beginning of summer (that are said to resemble a policeman’s helmet). But despite their attractive appearance, they are actually incredibly damaging to our native plants. As Himalayan Balsam can grow so quickly and densely, it out-competes and shades out other native species. They can also disperse hundreds of seeds up to 7 metres by ‘exploding’ when touched, and so can spread rapidly downstream along waterways. During the winter months they die back and leave river banks exposed and vulnerable to erosion.
Himalayan balsam flowers © R G Woods/Plantlife
The best way to get rid of this undesirable species, without chemicals, is to uproot them in the spring before they flower in the summer months. Himalayan Balsam is fairly easy to pull out of the ground as it has shallow roots, so a combination of uprooting and strimming is used to get rid of large clumps. The SNCV have been removing patches of Himalayan Balsam at Beddington for a few years, the work is usually carried out around this time of year before the plants get a chance to flower and spread their seeds. Efforts seem to have paid off though, because each year the patches of Himalayan balsam have shrunk in size.
Himalayan Balsam is so invasive that the Environment Agency estimate that it could cost as much as £300 million to totally remove it from Britain. Volunteers projects to try and eradicate this species have been fairly successful in some parts of the country, but this invasive species is very much with us for the moment.
If you’d like to learn more about how to identify invasive plants, or what to do if you come across them, then take a look at the links below for more information:
http://www.nonnativespecies.org/index.cfm?sectionid=58
http://www.thames21.org.uk/non-native-invasive-species/
Eleanor Kirby-Green
SNCV Biodiversity Assistant
